This invention relates to the field of hose clamp assemblies, more particularly, this invention relates to a spring liner that is associated with a hose clamp assembly, and allows the hose clamp to self-compensate for changes in elastic properties and diametric changes of the underlying hose and fittings.
Hose clamps are commonly utilized to join together hoses and fittings or connectors (referred to hereinafter as fittings), for example, within the automotive industry. Hose clamps, hose and fittings respond to changes in ambient temperature and system temperatures based on the thermal properties of the aforementioned components. Differing coefficients of thermal expansion of these components can result in thermally-induced reductions in clamping force, thus creating the potential for fluid or gas leakage. In addition, changes in elasticity of the hose materials over time due to creep, compression set, or deterioration can also reduce the clamping force and create the potential for fluid leakage.
Various types of spring liners used in conjunction with hose clamps are known. U.S. Pat. No. 6,000,104 discloses an annular insert band having two end sections that extend in the circumferential direction and overlap one another. One of the end sections may be shaped as a corrugated spring, which creates a spring force that tends to re-tension the clamp. The insert band may have resilient, corrugated tabs that project radially inward and create some additional re-tensioning force. This spring liner has two deficiencies. First, the insert band is flat so that hose material is squeezed out from under it as it is tightened circumferentially. Second, the axial corrugations and tabs create circumferentially non-uniform and localized forces, which are not well-suited to prevent fluid leakage.
U.S. Pat. No. 4,677,375 discloses an annular resilient insert band provided with two axially spaced inwardly directed peripheral beads which extend around the band. In between the two beads is an outwardly directed ridge in abutment with the inner face of the tensioning band of the clamp. As the clamp is tensioned or tightened, the beads are supposed to help to prevent the outward flow of the hose material, and the beads are supposed to deflect to provide a re-tensioning force. According to subsequent U.S. Pat. No. 5,630,255, the prior two-bead design ('375) failed to serve its intended function. The '255 patent sought to improve the movability of the beads in the radial and axial direction by adding a number of openings in the outwardly directed ridge. However, the abutment of the outward ridge against the inner face of the tensioning band was retained.
What is needed is a circumferentially corrugated insert spring liner for a hose clamp providing improved initial and long term sealing effect over that obtained with prior art hose clamp liner designs.